It is common practice to insert post cards, advertising order cards, and the like in a magazine during the binding process, so that the cards are either anchored permanently in the binding for tearing off by the customer or loosely inserted.
U.S. Pat. No. 4,456,241 illustrates a card feeding apparatus wherein the cards are fed downwardly from a stack one-by-one for transport to an appropriate inserter in a binding line. The stack of cards is supported at its leading edge on a stripper-type support, and the bottom card is engaged by a sucker cup which moves vertically into engagement with the bottom card and then draws the card downwardly, causing it to "flick" over the stripper support. The card is then advanced horizontally into a feeding or pick up position. While the apparatus disclosed in the above referenced patent performs satisfactorily, it employs a rather complicated mechanism to impart the necessary vertical and horizontal movements to the lowermost card of the stack.
In another prior feeding apparatus, the suction cup feed system has been replaced by a rotating card transport drum, which includes a circular suction opening on its peripheral surface. The drum is positioned to underlie and support the stack of cards, and as the drum rotates, a vacuum is drawn in the suction opening during its passage beneath the stack so as to engage the lowermost card and advance it forwardly into the nip of a conveyor feeding system.
The use of a rotating feed drum as described above provides a structurally simplified arrangement for engaging and advancing the lowermost card. However, when relatively thin cards of about 3 to 5 thousands of an inch are being handled, the force of the vacuum often tends to bleed through the lowermost card and also grip the next adjacent card, with the result that the two cards are fed together to the pick up point.
It is accordingly an object of the present invention to provide an apparatus for sequentially feeding cards from the bottom of a vertical stack, and which employs an improved card transport drum which avoids the disadvantages and limitations of the prior drums as described above.
It is a more particular object of the present invention to provide a card feeding apparatus which is highly efficient in sequentially delivering only a single card from the bottom of a vertical stack.
It is also an object of the present invention to provide an apparatus of the described type which is highly reliable, which is capable of working at the fastest commercial feeding speeds, and which is capable of operating continuously over long periods of time without attention, maintenance, or adjustment.